v3.8.0.1

Medical Claims Liability - Incurred Claims and Allocated Claims Adjustment Expenses (Details) - Health insurance product line claim in Millions, $ in Millions	Dec. 31, 2017 USD ($) claim	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Claims Development [Line Items]
Short-duration insurance contracts, incurred claims and allocated claim adjustment expense, net	$ 102,831
Short-duration insurance contracts, accident year 2015
Claims Development [Line Items]
Short-duration insurance contracts, incurred claims and allocated claim adjustment expense, net	30,310	$ 30,325	$ 30,619
Short-duration insurance contracts, expected development on reported claims	$ 0
Short-duration Insurance contracts, number of reported claims | claim	156.7
Short-duration insurance contracts, accident year 2016
Claims Development [Line Items]
Short-duration insurance contracts, incurred claims and allocated claim adjustment expense, net	$ 34,296	$ 34,655
Short-duration insurance contracts, expected development on reported claims	$ 48
Short-duration Insurance contracts, number of reported claims | claim	179.1
Short-duration insurance contracts, accident year 2017
Claims Development [Line Items]
Short-duration insurance contracts, incurred claims and allocated claim adjustment expense, net	$ 38,225
Short-duration insurance contracts, expected development on reported claims	$ 3,330
Short-duration Insurance contracts, number of reported claims | claim	192.0

X

- Definition

Short-duration Insurance Contracts, Incurred but Not Reported Liabilities and Expected Development on Reported Claims

+ References

No definition available.

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- Definition

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+ References

No definition available.

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- Definition

Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 4B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671311-158438

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- Definition

Number of reported claims for short-duration insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65670685&loc=SL65671317-158438

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